Interference-reducing system



' Dec. 8,1925- P. GOLDSTONE INTERFERENCE REDUCING SYSTEM 4 Sheets-Sheet 1 15 PM 4 I 15 17/nnrr 7 19 J 2 I I! v g 15; [1/

,75 -;75 Z0 J7LWW VJ7 INVENTOR A TORNE Y3 Dec. 8, 1925- 1.5 4.345

P. GOLDSTONE.

INTERFERENCE REDUCING SYSTEM Filed Sept. 10, 1921 4 Sheets-Sheet 2 I l I K f" A 19 g J7 1 I L 217 INVENTOR P. GOLDSTONE INTERFERENCE REDUCING SYSTEM Dec. 8, 1925. 1,564,345

Filed Sept. 10. 1921 4 Sheets-Sheet 3 Sig ion c.

INVENTOR ,4; ,4 TTORNEYJ' Patented Dec. 8, 1925. I

UNITEI STATES 1,564,345 PATENT OFFICE-.1

PHILIP GOLDSTONE, OF WOODI-IAVEN, NEVT YORK, ASSIGNOR TO GIBBS & HILL, OF NEW YORK, N. Y., A PARTNEIVI-IIP.

INTERFERENCE-REDUCING SYSTEM.

Application filed Eleptember To all whom it may concern:

Be it known that I, PHILIP Gonnsroivn, being a citizen of the United States, residing at \Voodhaven, in the county of Queens i and State of New York, have invented certain new and useful improvements in Interference-Reducing Systems, of which the following is a full, clear, and exact description.

This invention relates to electric power transmission or distributing systems. More specifically it relates to alternating current transmission or distributing systems and has for one of its principal objects to pro vide a method and means for reducing the interference between such systems and adjacent systems, such as those comprising conductors for transmitting intelligence telephonically, telegraphically or otherwise.

It is common practice to locate intelligence-conveying conductors, such as telephone or telegraph wires, along the same right of way with, and comparatively adjacent to, alternating current railway systems. By virtue of the relative proximity of two such systems objectionable currents,

r components of currents, have been superimposed by'the power system upon the intelligence-conveying system, seriously interfering with and impeding its proper functioning. This effect is lrnown as interference. This interference is due largely to two factors-the mutual induction between the systems, and the static effect of the power system. upon the. other. In accordance with my invention 1 reduce one, or preferably both, of these factors without losing the obvious acvantages of proximity of locationof the. two systems. Qbjeots and advantages, other than those set forth above, will appear as the invention hereinafter disclosed.

Referring to the drawings, which illustrate what I now consider preferred physical ibodiments of the invention,

1 a diagram illustrating the inven tion applied to a single section of a one track, single phase electric railway system.

2 is a view similar to Fig. 1 but illustratinga modified arrangement of con tact and balancing conductors.

F 3 a similar view illustrating one method of applying the invention to a double track road.

Fig. 4- is a diagram illustratin g the in 10, 1921. Serial No. 489,811.

vention as applied to 'a three phase A. C. railway, the primaries, and their connections, of the step-down transformers b'e'ing omitted.

Fig. 5 is a View similar to Fig. i, but illustrating an application of the invention to a. two-phase railway system;

Fig. 6 is a morecomplete diagram "illustrating an application of the invention to a two-track, single phase railwaysystem.

Fig. 7 is a diagram illustrating an application of the invention to a. single phase, double track railway system supplied from three phase high tension transmission lines.

In order to facilitate disclosureof the invention I have illustrated diagrammatically in Fig. 1, one section of a single trade-single phase A. C. railway transmission system. It will later appear that the invention may be applied to multi-track, or multi-phase,

or other systems. In Fig. 1 I have shown the usual high tension transmission or feed er conductors 10,10 supplied with alternating current, a-t'any desired voltage or .frequency, through a step-up transformer 11. Step-down transformers located at spaced substations or transformer stations are adapted to supply alternating propulsion current at a lower voltage tothe contact conductor, shown as a trolley wire 12, and to the return conductor 13, shown as a. track or ground return, of the railway. The primary windings 14, 16 are shown connected across the line'lO, 10, the secondary windings 15, 17 being connected across the line 12, 13. The connections and design, of the system thus far described, are such that when there'is no train between the stations, and conditions are otherwise normal,-there will be substantially no current flowing in the circuit l51217-1315. At this time-the E. M. F.s of the two transformers oppose and substantially neutralize each other. When a connection is established between the conductors 12-13,either due to the presence of a train in the section or short-circuit or otherwise, current flows in two main paths. Thus, in Fig. 1, current flows through a path l512181315 and anotheripath 17121813-17. The twosecondary windings l5 and l? are then operating in parallel to supply the load, i. e. the electrically propelledtrain 18. Calling the current flowing in the first mentioned path l, that in the second I, and the disproximated.

tancesbetween the moving. train and the StHtlOIIS D" and D respectively; the inductive interference between the line 12-13 and the intelligence-conveying conductors (not shown) paralleling the right of way, will be a minimum when the following relationship exists IIXDIIIIIXDII The reason for this is, other conditions being equal, that the E. M. F. impressed upon any given length of intelligence conveying line or lines by the power system is substantially directly proportional to the product of the particular length and the current flowing in the adjacent length of the line 1213. Therefore, if the above stated ideal relationship exists, the inductive E. M. F. impressed upon that portion of the intelligence-conveying system which lies between one substation and the moving load 18 will equal and. oppose and therefore balance out) that impressed upon the portion of the intelligence-conveying. system which lies between the other substation and the moving load.

However, in the absence of means other than thus far specifically described, the condition represented by the equation:

- IIXDIIIIIXDII cannot be maintained nor even closely ap Due to the shifting load the relationship of the E. M. F.s of the secondary windings 15 and 1? varies to a great extent, causing a departure from the ideal condition above set forth. And the magnitude of the objectionable inductive interference with the intelligence-conveying system increases with the extent of departure from such ideal current-distance relationship.

I provide a method and means for greatly reducing, if not totally eliminating such inductive interference. One form of means for eti'ecting this result is illustrated in Fig. 1 and may be constructed as follows. Each of the t vo transformers is provided with a secondary winding 15 and 17". The winding 1.5 is shown connected one end to the grounded end of the winding 15 and at its other end to one end of a line conductor 19 extending between stations. The winding 17 is similarly connected to the conductor 19 and winding 17 at the other station. Although other combinations of voltages and impedances may be successfully employed, effectiveness is ob tained when the number, size and position of conductors are so chosen that the branch consisting, in this instance, of the elements l5-12-17 has substantially the same impedance as the branch consisting of the elements 1519-17; so that the ratio of resistance to reactance in each of these two branches is substantially equal to the ratio of resistance toreactance in the other branch, and so that the voltage across the conductors 1213 is substantially equal to that across the conductors 19l3.

By virtue of the above described provisions and connections, the potential of the conductor 12, with respect to the conductor 13, at any instant will be substantially equal to but opposite to that of the conductor 19, with respect to the return conductor 13. The windings 15, 17 and conductor 19, together with their connections 15 1217, form'a means for short circuiting any difference of potential across the low tension side of the step-down transformers in the adjacent substations. In other words the circuit 12-15-15-19- 17-17-12 is a balancing circuit which in effect equalizes the E. M. F.s of the 'secondary windings of the spaced step-down transformers. The greater portion of the cross current, i. e. secondary current-flowing from one step-down, transformer at one station to the step-down transformer at the other, is carried by the conductors 19, 12 rather than by the conductors 12, 13. The result of the combination including the elements 151917 is that the condition represented by the equation is closely approximated, if not actually attained, no matter what position the load may occupy in the section between stations. It will therefore be understood I have reduced the inductive interference between the power system and the adjacent intelligence-conveying system (not shown) by a very substantial amount.

I have not only effected the last men tioned extremely important result but also have provided a method and means for reducing the static interference between the two systems. Such disturbances are commonly caused by the proximity of a comparatively high-voltage conductor to the intelligence conveying circuit and under certain conditions are very serious where a Contact conductor and ground return are employed. In such a case the voltage client of the contact conductor is: not balanced out nor appreciably offset by the return conductor which is at earth potential. However, in my system the cone uctor 19 is at all times at substantially equal but opposite potential with respect to the potential of the contact conductor 12, thus ofltsetting or neutralizing the static effect of the contact conductor upon the intelligence couveying system.

The invention may assume forms other than that above disclosed. Thus in Fig. 2, a view similar to Fig. 1, I have illustrated an arrangement in which the conductor 19 serves not only as a balancing conductor but also'as a contact conductor. And the conductor 12 serves both as a balancing conductor andas a contact conductor. Describing thissystem more fully, that portion of conductor 12 which lies between the section break 20 and one of the stations is employed as a contact conductor "and that portion of the conductor 19, which lies between the sectionbreak, and theother station is employed as the remainder of the contact conductor. In the main, the operation of the system illustrated in Fig. 2 is the same as that of the system illustrated in Fig.1, similar parts in the two Figs. being designated by the same reference numerals. However, the system illustrated in Fig. 2 possesses additional advantages. Assume that there are one or moretrains 18, 18 on each of opposite sides of the section break 20. The total load current is then divided between the conductors l2 and 19 thereby materially reducing the line voltage drop. Furthermore, bearing in mind that the potential of either of the conductors 12 and 19 is at all times substantially equal but opposite to that of the other of said conductors, the net or resultant current flowing through the track is greatly reduced.

If desirable, where the railway system is a two-track one, one of the conductors 12, 19 may be employed as the contact conductor for one track and the other of said conductors as the contact conductor for the other track. Such an arrangement is illustrated in Fig. 3 where the conductor 19 is the contact conductor for the track 13 and the conductor 12 is the contact conductor for the track 13. The operation and advantages of this form of the invention will be apparent upon inspection of the drawings and view of the foregoing description.

As previously stated, the invention is ap plicable, not only to single phase power transmission systems but, to multiphase systems. In Fig. 1 I have shown the invention applied to a three phase electric traction system. In this view. the elements 1.2-, 1 15, 15, 17, 17 and 19 will at once he recognized in "view of the detailed description of the similar elements in Fig. 1. For the sake of clarity, and to avoid surplus-age in illustration, I have omitted illustration of the high tension lines and the couplings and connections between these lines and the step-down transformer secondaries of the spaced stations. Such connections are well known to those skilled in the art. Instead of, employing one secondary winding 15 or 17 at each station across the contact and return conductors, three seconiilary windings 15, 21, 115 and 17, 22, 117, shown delta connected, are employed. lhe return conductor 1 -1 and the contact rozuluctors (now two in number) 12 and 112 constitute the three phases of the system; It willbe understood of course that the car or cars 118 may be provided with the necessary equipment to operate upon three phase current. In addition to the step-down transformer secondary section 15, 17 and 'conductor 19, there are provided additional balancing means comprising the step-down transformer secondary section 115 and 117 which bear the same relationship to th windings 115 and 117 respectively that the windings 15 and 17' bear to the windings 15 and 17 respectively and a conductor 119. The operation of this form of the invention will be readily understood in view of the above description and in view of the explanation set forth in connection with Fig. 1.

In Fig. 5, which is a view similar to Fig. 1, I have shown the invention applied to a two phase or quarter phase three-conductor electric traction system. The elements 12, 13, 15, 15, 17, 17 and 19 of one phase will again be recognized in View of the description in connection with Fig. 1. The other phase comprises the secondary windings 215, 217 connected by the contact conductor 212, and the balancing sections 215, 217" connected by the conductor 219. The operation of the system shown in Fig. 5 need not be described. Suflice it to say the train or trains 218 are equipped to be propelled by the current of the phases 12 13 and 21213.

In Figs. 1 to 5 I have shown the invention applied to single sections of railway systems and, to facilitate understanding of the invention, have omitted the auxiliary equipment. In practice all, or as many as desired, of those sections of the right of'way which'are paralleled by intelligence-conveying conductors would be equipped with one or another form of the interference-reducing means, and the system'would embodythe usual auxiliary apparatus. 111 Fig. '6 I have shown two adjacent sections of a two-track railway system embodying the invention. In this figure auxiliary apparatus such as oil switches or breakers, disconnecting switches, buses etc, are diagrammatically indicated at the three spaced stations A, 13 and C, This auxiliary apparatus is well knownby those skilled in the art and needs no description. Comparison of section 1 of Fig. 6 with Fig. 1 will indicate that'tjhe elements 12, 1.3, 141, 15, 15, 16, 17, 17and'19 and their connections are substantially the same, in an electrical sense, in these two illustrations. However, it will be noted that the primary windings 1 1, 16 of the s'te p down transformers for section 1 in Fig. 6 are supplied with single phase alternating current from different lines 1010 and 1O1O of high tension conductors, in Lurn supplied by separate step-up transformers n A LU lland 11. Section 1 also comprises two trackways including not only conductors 12, 13 as shown in F1 1. but a contact'conductor 12 and its return conductor The two lines 1213 and 12- 1if are adapted to be connected in parallel in section 1. The connections of the duplicate balancing conthictor 19* and also of the transformer 14, 15, 15" will be understood upon inspection of the diagrai'n.

Section breaks 1:20 and 120 are shown provided in the contact conductors 12 and 12 between sections 1 and Section 2 of Fig. 6 illustrates the application of the form of invention shown in Fig. 2, to a two-track road. Except for changes similar to those noted in dilfercntiating between section 1 and Fig. 1, section 2 of i 6 is the same as that shown in Fig. 2 in design and law of operation.

The operation of the system shown in Fig. 6 will now be obvious and detailed description thereof would com uto niere. ietition, in view of the foregoing, description of Fig. 1.

The system, one section of which is shown in Fig. 1 may be supplied with single phase high tension transmission as indicated in that figure, or may be supplied from multiphase high tension transmission wires by employing single-phase step-down transformers connected between the same phase in particular sections, suitably insulated from each other, so that one section of the line may be supplying phase 1 power, a second section-phase 2 power, a third sectionphase 3 power, and so on. Thus in Fig. 7 I have shown three sections of a single phase double track railway supplied by different phases of a three phase high tension transmission line or lines. Except for diiferences in the connections between the primaries of the step-clown transformers and the high tension lines, the apparatus and connections in any one sectional-e identical to those in any other section. And, except forthe addition of the conductors 12 13 and 19 and their connections (which need not be explained in detail) and the difference in connections of the primaries 1 1 and 16; the arrangement and operation of the system in each section of Fig. 7 are essentially the same as set forth in connection with Fig. 1. The lines 75, 76, 77 and175, 176 and 177 are supplied with three phase high tension A. Q, the frequency of the current in the two sets of line wires the same. lv loreover the E. M. F.s across conductors --76, 7677 and 75 7 7 are substantially in phase respectively with the E. M. F.s across conductors 115-476, 176177 and 175-177. It will be noted that the stepdown transformers of section 1 supplied wit phase 1 power from the conductors 7677 and 176-1775 2 power from the conductors 75'Z7 and those in section 3 are supplied with phase 3 power from the conductors 7576. The electrical design and operation of the system illustrated in Fig. 7 will be clearly understood in view of the foregoing description.

I wish to emphasize that while my invention has other important advantages, it is primarily designed to reduce interference between power systems and intelligenceconveying systems (such as telephone. or printing or other telegraph lines) which occupy the same or adjacent or more or less remote rights of way. To simplify illustra tion I have omitted, from each figure of drawings, illustration of the conductors of the intelligence-conveying system but it will be understood that they are present in conditions of actual practice.

In accordance with the requirements of the patent statutes l have disclosed now preferred forms of my in ention. It will til lerstood t the specific physical embodunents herein disclosed. are illustrated only diagrammatically and. to avoid confu sion and surplnsaee. more or less auxiliary apparatus such as rcuit b-reakersswitches etc, which may prove desirable in practice, have been omitted. However, with the present disclosure before him, a man skilled in the art to which the inventionpertains could maize and practice the invention. It is to be borne in mind also that while it is at present preferred to employ the various features and elements in the combinations described, some of these may be altered and others omitted, and some of the features of each modification may be embodied in the others, without interfering with the more general. results and effects outlined, and the invention extends to such. use within the scope of the appended claims.

That I claim is 1. A system, for reducing interference between an A. C. railway distribution system and juxtaposed intelligence-conveying conductors, comprising in combination, a contact conductor, a return conductor, spaced transformer windings connected in multiple with each other across said conductors, a third conductor substantially coextensive with said contact and return conductors, and means including additional transformer windings inductively coupled to said first named transformer windings and connected to said third conductor for in effect equalizing the terminal E. M. F.s of said first named transformer windings.

2. A system, for reducing interference between an A. C. railway distribution system and juxtaposed intelligence-conveying conductors, comprising in combination, a con tact conductor, a return conductor, spaced those in section 2 are supplied with phase transformer windings connected in multipie with each other across said coiuluctors, a third conductor substantially coextensive with said contact and return conductors, and means including additional transformer windings inductively coupled to said first named tra ormer windin s and connected to said :d conductor Tor in effect equalizing the terminal E. El. it's of said first named transfer-inc windings and for maintaining the potential of said third conductor substantially equal and opposite to that of said contact conductor.

3. A system, for reducing interference be tween an A. (l. railway distribution system and juxtaposed intcliigenes-conveying conductors, comprising in combination, a contact comluctor, a return conductor, spaced transformer windings connected in multiple with each other across said conductors, and means including a third conductor extending bot een and connected to said transformer windings for automatically and in effect equalizing the terminal E. M. F.s of said windings."

i. A system, for reducing interference between an A. (I. railway distribution system and juxtaposed intelligenceconveying conductors, comprising in combination, conductors including a contact conductor and a return conductor, a transformer including a winding connected across said conductors, a second transformer including a winding connected across said conductors in multiple with said first named transformer winding but spaced therefrom, and means inherent in said transformers and conductors for in effect preventing differences of potential tending to form between said windings.

A system, for reducing interference between an A. C. railway distribution system and juxtaposed intelligence-conveying conductors, comprising in combination, a contact conductor, a return conductor, spaced transformer windings connected in multiple with each other across said conductors, and means including windings inductively coupled to said first named windings for automatically and in effect equalizing the terminal E. M. F.s of said first named windings.

6. A railway distribution system comprising in combination, a plurality of substantially coextensive contact conductors, a return conductor, spaced transformer windings connected in multiple with each other across said return conductor and one of said first named conductors, means for automatically and in effect equalizing the terminal E. M. F.s of said windings, and means for maintaining the potential of one of said contact conductors opposite to that of another of said contact conductors.

7. A railway distribution system comprising in combination, a plurality of substantially coextensive conductors one of which constitutes a contact conductor tln'oughout substantially its entire length for one track and another of which conductors constitutes a contact conductor throughout substantially its entire length for a different track, a return conductor, spaced transformer windings"connected in multiple with each :rther across said return conductor and one of said first named conductors, means for automatically and in effect equalizing the terminal E. M, F.s of said windings, and means for maintaining the potential of one of said contact conductors opposite to that of another of said contact conductors.

8. An electrical system comprising a supply circuit, a distribution circuit including a plurality of working conductors and a feeder conductor, and a plural-winding transformer having one winding connected to said supply circuit and points in other windings connected to said feeoer and said working conductors, the windings of said transformer being so related to said conductors and to each other as to reduce the external inductive interference effect of said distribution circuit to a negligible value.

9. An electrical system comprising a supply circuit, a distribution circuit including a plurality of working conductors and a feeder conductor, a plural-winding transformer having one winding connected to said supply circuit and points in other windings connected to said feeder and said Working conductors, and a plurality of trans former windings remotely located from said other windings and connected in a similar manner, the windings of said plural-winding transformer being so related to each other and to said conductors and the last-named transformer windings as to reduce the external inductive interference effect of said distribution circuit to a negligible value.

10. An electrical railway system comprising a supply circuit, a distribution circuit including a trolley conductor, a track conductor and a feeder conductor, and a threewinding transformer having a single primary winding connected across said supply circuit, the junction-point of the secondary windings being, connected to said track conductor and an outer terminal of said secondary windings being respectively connected to said feeder conductor and said trolley conductor, the impedances of the windings of said transformer being so proportioned relative to the impedances of said conductors and to each other that under operating conditions the external inductive interference effect of said distribution circuit is substantially zero.

11. An electrical railway system comprising a supply circuit, a distribution circuit including a trolley conductor, a track conductor and a feeder conductor, and a three- Winding transformer having a single primary Winding connected across said supply circuit, the junction-point of the secondary windings being connected to said track conductor and an outer terminal of said secondary windings being respectively connected to said feeder conductor and said trolley conductor, the impedances of the windings of said transformer being so related to the impedances of said conductors and to each other and the flow of currents being such that the inductive interference effect of said distribution circuit upon a parallel. intelligence-communication conductor is substantially zero.

12. An electrical system comprising in combination, a supply circuit, a distribution circuit including a plurality of Working conductors and a feeder conductor, a plurality of transformers remotely located with. respect to each other and having their primary windings connected to said supply circuit and having points of their secondary Windings connected to said feeder and Working conductors, the windings of said transformers being so related to said conductors and to each other as to reduce the external inductive interference eifect of the said distribution circuit to a negligible value.

13.An electrical system comprising in combination, a supply circuit, a distribu tion circuit including a plurality of Working conductors and a feeder conductor, a plurality of transformers remotely located With respect to each other and having their primary windings connected. to said supply circuit and having points of their secondary windings connected to said feeders and Working conductors, the primary of each of said transformers being distinct from the secondary, the windings of said transformers being so related to said conductors and to each other as to reduce the external inductive interference effect of the said distribution circuit to a ne ligible value.

In testimony whereof I hereto afiix my signature.

PHILIP GOLDSTONE. 

